i just build aussieamplifiers symmetrical 400's amps, and they are 200 into 8 ohms and 400 into 4.....bass is terrific! effortless for sure and VERY tight and VERY punchy and VERY articulate. You might be able to increase the rail voltage slightly, if you have more outputs, like 12 per channel rather than 8...and better driver transistors, such as mje15032 and 15033 ...i've used them w/ great sucess w/ 68v rails. If you try 75v or 80...you might get a little more punch into 8 ohms and less into 4...but i personnally think 200 watts is a lot. 250 is about .5-1 db greater...and 300 is about 1.5 db greater than 200. Go w/ recommended rail voltage...70v. Later!